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dstate.c

/* dstate.c - Network UPS Tools driver-side state management

   Copyright (C) 2003  Russell Kroll <rkroll@exploits.org>

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/

#include <stdio.h>
#include <stdarg.h>
#include <sys/stat.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

#include "common.h"
#include "dstate.h"
#include "state.h"
#include "parseconf.h"

      static      int   sockfd = -1, stale = 1, alarm_active = 0;
      static      struct      st_tree_t   *dtree_root = NULL;
      static      struct      conn_t      *connhead = NULL;
      static      struct      cmdlist_t *cmdhead = NULL;
      static      char  *sockfn = NULL;
      static      char  status_buf[ST_MAX_VALUE_LEN],
                  alarm_buf[ST_MAX_VALUE_LEN];

      struct      ups_handler upsh;

/* this may be a frequent stumbling point for new users, so be verbose here */
static void sock_fail(const char *fn)
{
      int   sockerr;
      struct      passwd      *user;

      /* save this so it doesn't get overwritten */
      sockerr = errno;

      /* dispense with the usual upslog stuff since we have stderr here */

      printf("\nFatal error: unable to create listener socket\n\n");
      printf("bind %s failed: %s\n", fn, strerror(sockerr));

      user = getpwuid(getuid());

      if (!user)
            fatal_with_errno(EXIT_FAILURE, "getpwuid");

      /* deal with some common problems */
      switch (errno) {
            case EACCES:
                  printf("\nCurrent user: %s (UID %d)\n\n",
                        user->pw_name, (int)user->pw_uid);

                  printf("Things to try:\n\n");
                  printf(" - set different owners or permissions on %s\n\n", 
                        dflt_statepath());
                  printf(" - run this as some other user "
                        "(try -u <username>)\n");
                  break;

            case ENOENT:
                  printf("\nThings to try:\n\n");
                  printf(" - mkdir %s\n", dflt_statepath());
                  break;

            case ENOTDIR:
                  printf("\nThings to try:\n\n");
                  printf(" - rm %s\n\n", dflt_statepath());
                  printf(" - mkdir %s\n", dflt_statepath());
                  break;
      }
      
      /*
       * there - that wasn't so bad.  every helpful line of code here 
       * prevents one more "help me" mail to the list a year from now
       */

      printf("\n");
      fatalx(EXIT_FAILURE, "Exiting.");
}

static int open_sock(const char *fn)
{
      int   ret, fd;
      struct      sockaddr_un ssaddr;

      fd = socket(AF_UNIX, SOCK_STREAM, 0);

      if (fd < 0)
            fatal_with_errno(EXIT_FAILURE, "Can't create a unix domain socket");

      /* keep this around for the unlink() when exiting */
      sockfn = xstrdup(fn);

      ssaddr.sun_family = AF_UNIX;
      snprintf(ssaddr.sun_path, sizeof(ssaddr.sun_path), "%s", sockfn);

      unlink(sockfn);

      /* group gets access so upsd can be a different user but same group */
      umask(0007);

      ret = bind(fd, (struct sockaddr *) &ssaddr, sizeof ssaddr);

      if (ret < 0)
            sock_fail(sockfn);

      ret = chmod(sockfn, 0660);

      if (ret < 0)
            fatal_with_errno(EXIT_FAILURE, "chmod(%s, 0660) failed", sockfn);

      ret = listen(fd, DS_LISTEN_BACKLOG);

      if (ret < 0)
            fatal_with_errno(EXIT_FAILURE, "listen(%d, %d) failed", fd, DS_LISTEN_BACKLOG);

      return fd;
}

static void conn_del(struct conn_t *target)
{
      struct      conn_t      *tmp, *last = NULL;

      tmp = connhead;

      while (tmp) {
            if (tmp == target) {

                  if (last)
                        last->next = tmp->next;
                  else
                        connhead = tmp->next;

                  pconf_finish(&tmp->ctx);

                  free(tmp);
                  return;
            }

            last = tmp;
            tmp = tmp->next;
      }

      upslogx(LOG_ERR, "Tried to delete a bogus state connection");
}

static void send_to_all(const char *fmt, ...)
{
      int   ret;
      va_list     ap;
      char  buf[ST_SOCK_BUF_LEN];
      struct      conn_t      *tmp, *tmpnext;

      va_start(ap, fmt);
      vsnprintf(buf, sizeof(buf), fmt, ap);
      va_end(ap);

      tmp = connhead;

      while (tmp) {
            tmpnext = tmp->next;

            ret = write(tmp->fd, buf, strlen(buf));

            if ((ret < 1) || (ret != (int) strlen(buf))) {
                  upsdebugx(2, "write %d bytes to socket %d failed",
                        strlen(buf), tmp->fd);

                  close(tmp->fd);
                  conn_del(tmp);
            }

            tmp = tmpnext;
      }
}

static int send_to_one(struct conn_t *conn, const char *fmt, ...)
{
      int   ret;
      va_list     ap;
      char  buf[ST_SOCK_BUF_LEN];

      va_start(ap, fmt);
      vsnprintf(buf, sizeof(buf), fmt, ap);
      va_end(ap);

      ret = write(conn->fd, buf, strlen(buf));

      if ((ret < 1) || (ret != (int) strlen(buf))) {
            upsdebugx(2, "write to fd %d failed", conn->fd);

            close(conn->fd);
            conn_del(conn);

            return 0;   /* failed */
      }

      return 1;   /* OK */
}

static void conn_add(int fd)
{
      int   acc, ret;
      struct      conn_t      *tmp, *last;
      struct      sockaddr_un sa;
      socklen_t   salen;

      salen = sizeof(sa);
      acc = accept(fd, (struct sockaddr *) &sa, &salen);

      if (acc < 0) {
            upslog_with_errno(LOG_ERR, "accept on unix fd failed");
            return;
      }

      /* enable nonblocking I/O */

      ret = fcntl(acc, F_GETFL, 0);

      if (ret < 0) {
            upslog_with_errno(LOG_ERR, "fcntl get on unix fd failed");
            close(acc);
            return;
      }

      ret = fcntl(acc, F_SETFL, ret | O_NDELAY);

      if (ret < 0) {
            upslog_with_errno(LOG_ERR, "fcntl set O_NDELAY on unix fd failed");
            close(acc);
            return;
      }     

      tmp = last = connhead;

      while (tmp) {
            last = tmp; 
            tmp = tmp->next;
      }

      tmp = xmalloc(sizeof(struct conn_t));
      tmp->fd = acc;
      tmp->next = NULL;

      pconf_init(&tmp->ctx, NULL);

      if (last)
            last->next = tmp;
      else
            connhead = tmp;

      upsdebugx(3, "new connection on fd %d", acc);
}

static int st_tree_dump_conn(struct st_tree_t *node, struct conn_t *conn)
{
      int   ret;
      struct      enum_t      *etmp;

      if (!node)
            return 1;   /* not an error */

      if (node->left) {
            ret = st_tree_dump_conn(node->left, conn);

            if (!ret)
                  return 0;   /* write failed in the child */
      }

      if (!send_to_one(conn, "SETINFO %s \"%s\"\n", node->var, node->val))
            return 0;   /* write failed, bail out */

      /* send any enums */
      for (etmp = node->enum_list; etmp != NULL; etmp = etmp->next)
            if (!send_to_one(conn, "ADDENUM %s \"%s\"\n",
                  node->var, etmp->val))
                  return 0;

      /* provide any auxiliary data */
      if (node->aux != 0) {
            if (!send_to_one(conn, "SETAUX %s %d\n", node->var, node->aux))
                  return 0;
      }

      /* finally report any flags */
      if (node->flags != 0) {
            char  flist[SMALLBUF];

            /* build the list */
            snprintf(flist, sizeof(flist), "%s", node->var);

            if (node->flags & ST_FLAG_RW)
                  snprintfcat(flist, sizeof(flist), " RW");
            if (node->flags & ST_FLAG_STRING)
                  snprintfcat(flist, sizeof(flist), " STRING");

            send_to_one(conn, "SETFLAGS %s\n", flist);
      }

      if (node->right)
            return st_tree_dump_conn(node->right, conn);

      return 1;   /* everything's OK here ... */
}

static int cmd_dump_conn(struct conn_t *conn)
{
      struct      cmdlist_t   *tmp;

      for (tmp = cmdhead; tmp != NULL; tmp = tmp->next) {
            if (!send_to_one(conn, "ADDCMD %s\n", tmp->name))
                  return 0;
      }

      return 1;
}

static int sock_arg(struct conn_t *conn, int numarg, char **arg)
{
      if (numarg < 1)
            return 0;

      if (!strcasecmp(arg[0], "DUMPALL")) {

            /* first thing: the staleness flag */
            if (stale == 1)
                  if (!send_to_one(conn, "DATASTALE\n"))
                        return 1;

            if (!st_tree_dump_conn(dtree_root, conn))
                  return 1;

            if (!cmd_dump_conn(conn))
                  return 1;

            if (stale == 0)
                  if (!send_to_one(conn, "DATAOK\n"))
                        return 1;

            send_to_one(conn, "DUMPDONE\n");
            return 1;
      }

      if (!strcasecmp(arg[0], "PING")) {
            send_to_one(conn, "PONG\n");
            return 1;
      }

      if (numarg < 2)
            return 0;

      /* INSTCMD <cmdname> [<value>]*/
      if (!strcasecmp(arg[0], "INSTCMD")) {

            /* try the new handler first if present */
            if (upsh.instcmd) {
                  if (numarg > 2) {
                        upsh.instcmd(arg[1], arg[2]);
                        return 1;
                  }
                  upsh.instcmd(arg[1], NULL);
                  return 1;
            }

            upslogx(LOG_NOTICE, "Got INSTCMD, but driver lacks a handler");
            return 1;
      }

      if (numarg < 3)
            return 0;

      /* SET <var> <value> */
      if (!strcasecmp(arg[0], "SET")) {

            /* try the new handler first if present */
            if (upsh.setvar) {
                  upsh.setvar(arg[1], arg[2]);
                  return 1;
            }

            upslogx(LOG_NOTICE, "Got SET, but driver lacks a handler");
            return 1;
      }

      /* unknown */
      return 0;
}

static void log_unknown(int numarg, char **arg)
{
      int   i;

      upslogx(LOG_INFO, "Unknown command on socket: ");

      for (i = 0; i < numarg; i++)
            upslogx(LOG_INFO, "arg %d: %s", i, arg[i]);
}

static int sock_read(struct conn_t *conn)
{
      int   i, ret;
      char  ch;

      for (i = 0; i < DS_MAX_READ; i++) {

            ret = read(conn->fd, &ch, 1);

            if (ret < 1) {

                  /* short read = no parsing, come back later */
                  if ((ret == -1) && (errno == EAGAIN))
                        return 0;

                  /* some other problem */
                  return -1;  /* error */
            }

            ret = pconf_char(&conn->ctx, ch);

            if (ret == 0)           /* nothing to parse yet */
                  continue;

            if (ret == -1) {
                  upslogx(LOG_NOTICE, "Parse error on sock: %s",
                        conn->ctx.errmsg);

                  return 0;   /* nothing parsed */
            }

            /* try to use it, and complain about unknown commands */
            if (!sock_arg(conn, conn->ctx.numargs, conn->ctx.arglist))
                  log_unknown(conn->ctx.numargs, conn->ctx.arglist);

            return 1;   /* we did some work */
      }

      return 0;   /* fell out without parsing anything */
}

static void conn_close_all(void)
{
      struct      conn_t      *tmp, *next;

      tmp = connhead;

      while (tmp) {
            next = tmp->next;

            close(tmp->fd);
            free(tmp);

            tmp = next;
      }
}           

/* interface */

void dstate_init(const char *prog, const char *port)
{
      char  sockname[SMALLBUF];

      /* do this here for now */
      signal(SIGPIPE, SIG_IGN);

      if (port != NULL)
            snprintf(sockname, sizeof(sockname), "%s/%s-%s",
                  dflt_statepath(), prog, port);
      else
            snprintf(sockname, sizeof(sockname), "%s/%s",
                  dflt_statepath(), prog);

      sockfd = open_sock(sockname);

      upsdebugx(2, "dstate_init: sock %s open on fd %d", sockname, sockfd);
}

/* extrafd: provided for waking up based on the driver's UPS fd */
int dstate_poll_fds(int interval, int extrafd)
{
      int   ret, maxfd;
      fd_set      rfds;
      struct      timeval tv;
      struct      conn_t      *tmp, *tmpnext;

      tv.tv_sec = interval;
      tv.tv_usec = 0;

      FD_ZERO(&rfds);
      FD_SET(sockfd, &rfds);

      maxfd = sockfd;

      if (extrafd != -1) {
            FD_SET(extrafd, &rfds);

            if (extrafd > maxfd)
                  maxfd = extrafd;
      }

      for (tmp = connhead; tmp != NULL; tmp = tmp->next) {
            FD_SET(tmp->fd, &rfds);

            if (tmp->fd > maxfd)
                  maxfd = tmp->fd;
      }

      ret = select(maxfd + 1, &rfds, NULL, NULL, &tv);

      if (ret == 0)
            return 0;

      if (ret < 0) {
            /* ignore interruptions from signals */
            if (errno != EINTR)
                  upslog_with_errno(LOG_ERR, "select unix sockets failed");
            return 0;
      }

      if (FD_ISSET(sockfd, &rfds))
            conn_add(sockfd);

      tmp = connhead;

      while (tmp) {
            tmpnext = tmp->next;

            if (FD_ISSET(tmp->fd, &rfds)) {
                  if (sock_read(tmp) < 0) {
                        close(tmp->fd);
                        conn_del(tmp);
                  }
            }

            tmp = tmpnext;
      }

      /* tell the caller if that fd woke up */
      if ((extrafd != -1) && (FD_ISSET(extrafd, &rfds)))
            return 1;

      return 0;
}     

int dstate_setinfo(const char *var, const char *fmt, ...)
{
      int   ret;
      char  value[ST_MAX_VALUE_LEN];
      va_list     ap;

      va_start(ap, fmt);
      vsnprintf(value, sizeof(value), fmt, ap);
      va_end(ap);

      ret = state_setinfo(&dtree_root, var, value);

      if (ret == 1)
            send_to_all("SETINFO %s \"%s\"\n", var, value);

      return ret;
}

int dstate_addenum(const char *var, const char *fmt, ...)
{
      int   ret;
      char  value[ST_MAX_VALUE_LEN];
      va_list     ap;

      va_start(ap, fmt);
      vsnprintf(value, sizeof(value), fmt, ap);
      va_end(ap);

      ret = state_addenum(dtree_root, var, value);

      if (ret == 1)
            send_to_all("ADDENUM %s \"%s\"\n", var, value);

      return ret;
}

void dstate_setflags(const char *var, int flags)
{
      struct      st_tree_t   *sttmp;
      char  flist[SMALLBUF];

      /* find the dtree node for var */
      sttmp = state_tree_find(dtree_root, var);

      if (!sttmp) {
            upslogx(LOG_ERR, "dstate_setflags: base variable (%s) "
                  "does not exist", var);
            return;
      }

      if (sttmp->flags == flags)
            return;           /* no change */

      sttmp->flags = flags;

      /* build the list */
      snprintf(flist, sizeof(flist), "%s", var);

      if (flags & ST_FLAG_RW)
            snprintfcat(flist, sizeof(flist), " RW");
      if (flags & ST_FLAG_STRING)
            snprintfcat(flist, sizeof(flist), " STRING");

      /* update listeners */
      send_to_all("SETFLAGS %s\n", flist);
}

void dstate_setaux(const char *var, int aux)
{
      struct      st_tree_t   *sttmp;

      /* find the dtree node for var */
      sttmp = state_tree_find(dtree_root, var);

      if (!sttmp) {
            upslogx(LOG_ERR, "dstate_setaux: base variable (%s) "
                  "does not exist", var);
            return;
      }

      if (sttmp->aux == aux)
            return;           /* no change */

      sttmp->aux = aux;

      /* update listeners */
      send_to_all("SETAUX %s %d\n", var, aux);
}

const char *dstate_getinfo(const char *var)
{
      return state_getinfo(dtree_root, var);
}

void dstate_addcmd(const char *cmdname)
{
      int   ret;

      ret = state_addcmd(&cmdhead, cmdname);

      /* update listeners */
      if (ret == 1)
            send_to_all("ADDCMD %s\n", cmdname);
}

int dstate_delinfo(const char *var)
{
      int   ret;

      ret = state_delinfo(&dtree_root, var);

      /* update listeners */
      if (ret == 1)
            send_to_all("DELINFO %s\n", var);

      return ret;
}

int dstate_delenum(const char *var, const char *val)
{
      int   ret;

      ret = state_delenum(dtree_root, var, val);

      /* update listeners */
      if (ret == 1)
            send_to_all("DELENUM %s \"%s\"\n", var, val);

      return ret;
}

int dstate_delcmd(const char *cmd)
{
      int   ret;

      ret = state_delcmd(&cmdhead, cmd);

      /* update listeners */
      if (ret == 1)
            send_to_all("DELCMD %s\n", cmd);

      return ret;
}

void dstate_free(void)
{
      if (sockfd != -1) {
            close(sockfd);
            sockfd = -1;

            if (sockfn) {
                  unlink(sockfn);
                  free(sockfn);
                  sockfn = NULL;
            }
      }

      state_infofree(dtree_root);
      dtree_root = NULL;
      
      state_cmdfree(cmdhead);
      cmdhead = NULL;

      conn_close_all();
}

const struct st_tree_t *dstate_getroot(void)
{
      return dtree_root;
}

const struct cmdlist_t *dstate_getcmdlist(void)
{
      return cmdhead;
}

void dstate_dataok(void)
{
      if (stale == 1) {
            stale = 0;
            send_to_all("DATAOK\n");
      }
}

void dstate_datastale(void)
{
      if (stale == 0) {
            stale = 1;
            send_to_all("DATASTALE\n");
      }
}

int dstate_is_stale(void)
{
      return stale;
}

/* ups.status management functions - reducing duplication in the drivers */

/* clean out the temp space for a new pass */
void status_init(void)
{
      memset(&status_buf, '\0', sizeof(status_buf));
}

/* add a status element */
void status_set(const char *buf)
{
      /* separate with a space if multiple elements are present */
      if (strlen(status_buf) != 0)
            snprintfcat(status_buf, sizeof(status_buf), " %s", buf);
      else
            snprintfcat(status_buf, sizeof(status_buf), "%s", buf);
}

/* write the status_buf into the externally visible dstate storage */
void status_commit(void)
{
      if (alarm_active)
            dstate_setinfo("ups.status", "ALARM %s", status_buf);
      else
            dstate_setinfo("ups.status", "%s", status_buf);
}

/* similar handlers for ups.alarm */

void alarm_init(void)
{
      memset(&alarm_buf, '\0', sizeof(alarm_buf));
}

void alarm_set(const char *buf)
{
      if (strlen(alarm_buf) != 0)
            snprintfcat(alarm_buf, sizeof(alarm_buf), " %s", buf);
      else
            snprintfcat(alarm_buf, sizeof(alarm_buf), "%s", buf);
}

/* write the status_buf into the info array */
void alarm_commit(void)
{
      if (strlen(alarm_buf) != 0) {
            dstate_setinfo("ups.alarm", "%s", alarm_buf);
            alarm_active = 1;
      } else {
            dstate_delinfo("ups.alarm");
            alarm_active = 0;
      }
}

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